﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Data;
using System.Globalization;
using System.Windows;

namespace AppToolkit.WPF.UI.Converters
{
    /// <summary>
    /// <see cref="IValueConverter"/> implementation that negates the bound boolean value.
    /// </summary>
    [ValueConversion(typeof(bool), typeof(bool))]
    public class FlipBoolConverter : IValueConverter
    {
        /// <summary>
        /// Static instance avoid instantiating the converter multiple times.
        /// </summary>
        public static FlipBoolConverter Instance = new FlipBoolConverter();

        /// <summary>
        /// Converts a value. 
        /// </summary>
        /// <returns>
        /// A converted value. If the method returns null, the valid null value is used.
        /// </returns>
        /// <param name="value">The value produced by the binding source.</param><param name="targetType">The type of the binding target property.</param><param name="parameter">The converter parameter to use.</param><param name="culture">The culture to use in the converter.</param>
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (null == value)
                return DependencyProperty.UnsetValue;
            return !((bool)value);
        }

        /// <summary>
        /// Converts a value. 
        /// </summary>
        /// <returns>
        /// A converted value. If the method returns null, the valid null value is used.
        /// </returns>
        /// <param name="value">The value that is produced by the binding target.</param><param name="targetType">The type to convert to.</param><param name="parameter">The converter parameter to use.</param><param name="culture">The culture to use in the converter.</param>
        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            return !((bool)value);
        }
    }
}
